The present invention relates to a series of new 4-anilinoquinazoline derivatives, to a process for their preparation and to their use as analgesic and anti-inflammatory agents.
A wide range of analgesic and anti-inflammatory agents is available, suitable for treating pain of all intensity from mild (treated with aspirin, paracetamol or the like) to intense (treated with a narcotic analgesic, such as morphine or pentazocine). However, all of these known compounds have side effects, which may range from stomach irritation in the case of aspirin to dizziness, drowsiness and nausea and, in the case of the narcotic analgesics, may include dependence. The incidence and severity of these side effects varies from person to person and there is, therefore, a continuing need for new classes of analgesic for administration to persons to whom administration of existing analgesics would be inappropriate.
We have now surprisingly discovered that a class of 4-anilinoquinazoline derivatives possesses analgesic and anti-inflammatory activity comparable with, but in many cases substantially better than, that of aspirin. Although aminoquinazolines, including 4-anilinoquinazoline and 4-anilino-6-chloroquinazoline, are known [see, for example, J. Org. Chem., 41, 2646 (1976) and U.S. Pat. No. 3,985,749], they have hitherto been proposed for use in the treatment of coccidiosis and we are not aware of any prior suggestions that they have analgesic or anti-inflammatory activity.